Apparatuses and Methods for Supporting Bow Limbs

ABSTRACT

The present disclosure generally pertains to apparatuses and methods for supporting bow limbs. In accordance with one exemplary embodiment of the present disclosure, a T-shaped insert is inserted into each prong of a forked limb of an archery bow. An axle on which a cam is mounted passes through each insert in the forked limb. Each such insert helps to redistribute the load exerted by the axle in a manner so that the limb can better withstand the load thereby extending the useful life of the bow.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 60/834,713, entitled “Apparatuses and Methods for Supporting Bow Limbs,” and filed on Aug. 1, 2006, which is incorporated herein by reference.

RELATED ART

Many conventional archery bows have at least one cam mounted at a respective end of a bow limb. There are generally two types of bow limbs, solid and split. In either case, the end of a bow limb supporting a cam is typically forked such that it has two prongs separated by a gap. An axle passes through each prong, and the cam is mounted on the axle between the prongs. At least one cord is secured to the cam, which rotates when a user pulls the cord. The pulling of the cord also typically deforms the bow limb. The cam can be spring-loaded such that it returns to its original position when the user releases the cord thereby launching a projectile, such as an arrow, that has been positioned against the cord. Releasing of the cord also allows the deformed bow limb to return to its original position as the projectile is being launched, thereby increasing the momentum and velocity of the projectile.

Drawing of the cord by a user to launch projectiles causes significant force to be applied to the bow limb, particularly at the point where the axle passes through the limb. In this regard, forces caused by the drawing of the cord generally pass into the limb through the axle on which the cam is mounted. Repetitive drawing of the cord causes mechanical fatigue at such point eventually resulting in mechanical failure of the bow limb.

Moreover, improved bow designs enabling bows to better handle the forces and stresses caused by repeated use are generally desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Furthermore, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 depicts a conventional archery bow.

FIG. 2 depicts a forked limb of the archery bow depicted in FIG. 1.

FIG. 3 depicts an archery bow in accordance with an exemplary embodiment of the present disclosure.

FIG. 4 depicts a forked limb of the bow depicted in FIG. 3.

FIG. 5 depicts a side view of the forked limb depicted in FIG. 4 with a cam mounted thereon.

FIG. 6 depicts a planar view of the forked limb depicted in FIG. 5 with the cam removed for illustrative purposes.

FIG. 7 depicts a side view of the forked limb depicted in FIG. 6.

FIG. 8 depicts a planar view of the forked limb depicted in FIG. 6.

FIG. 9 depicts a three-dimensional view of the forked limb depicted in FIG. 7.

FIG. 10 depicts an end view of an insert that is positioned in a prong of the forked limb depicted in FIG. 6.

FIG. 11 depicts a side view of the insert depicted in FIG. 10.

FIG. 12 depicts a side view of a prong of the conventional forked limb depicted in FIG. 2.

FIG. 13 depicts a side view of the forked limb depicted in FIG. 5 with the insert removed for illustrative purposes.

FIG. 14 depicts an end view of a prong of a forked bow limb in accordance with an exemplary embodiment of the present disclosure.

FIG. 15 depicts a side view of the prong depicted in FIG. 14.

FIG. 16 depicts a top view of the prong depicted in FIG. 14.

FIG. 17 depicts an end view of the prong depicted in FIG. 14 after a head of an insert in the prong has been beveled.

FIG. 18 depicts a planar view of the prong depicted in FIG. 17.

FIG. 19 depicts an end view of a prong of a forked bow limb in accordance with an exemplary embodiment of the present disclosure.

FIG. 20 depicts a side view of the prong depicted in FIG. 19.

FIG. 21 depicts planar view of the prong depicted in FIG. 19.

FIG. 22 depicts an exemplary bow having an insert depicted in FIG. 19 with a weight attached to the insert.

FIG. 23 depicts a planar view of an exemplary prong that has been cut to form a channel for receiving an exemplary insert in accordance with the present disclosure.

FIG. 24 depicts an end view of the prong depicted by FIG. 23.

FIG. 25 is a flow chart illustrating an exemplary method for manufacturing a bow having an insert in accordance with the present disclosure.

FIG. 26 depicts an end view of an exemplary insert to be positioned in the channel of the prong depicted in FIG. 23.

FIG. 27 depicts a side view of the insert depicted in FIG. 26.

FIG. 28 depicts an end view of the prong of FIG. 23 after the insert of FIG. 26 has been positioned in the channel of the prong.

FIG. 29 depicts a side view of the prong depicted in FIG. 28.

FIG. 30 depicts a side view of the prong depicted in FIG. 29 after the insert positioned in the prong has been shaped via a sanding process.

DETAILED DESCRIPTION

The present disclosure generally pertains to apparatuses and methods for supporting bow limbs. In accordance with one exemplary embodiment of the present disclosure, inserts are respectively inserted into prongs of a forked limb of an archery bow. An axle on which a cam is mounted passes through each insert in the forked limb. Each such insert helps to redistribute a load exerted by the axle in a manner so that the limb can better withstand the load thereby extending the useful life of the bow.

FIG. 1 depicts a conventional bow 20 having forked limbs 19, 21. As shown by FIG. 2, the end of the limb 21 has two prongs 22, 23 separated by a gap 24. An axle 25 passes through the gap 24, and a rotatable cam 34 is mounted on the axle 25. In this regard, the axle 25 passes through the cam 34, and the cam 34 may rotate about the axle 25. At least one cord 26 is secured to the cam 34, and the cord 26 is secured to another cam 33 mounted on another end of the bow 20.

A user may abut an arrow (not shown) against the cord 26 and pull the cord 26 thereby rotating each cam 33, 34. The cams 33, 34 are spring loaded such that, when the user releases the cord 26, the cams 33, 34 rapidly return to their original positions projecting the arrow from the bow 20 at a great speed and with great force. Further, the bow limbs 19, 21 typically deform when the cord 26 is drawn by a user and return to their original positions when the cord 26 is released, thereby increasing the arrow's momentum.

During the time that the cord 26 is drawn by the user, great force is exerted on the limbs 19, 21. In this regard, referring to FIG. 2, tension from the drawn cord 26 is exerted on the axle 25 by the cam 34 and absorbed by the limb 21. Eventually, the limb 21 may fracture or otherwise fail due primarily from mechanical fatigue induced by repeated exertion of the foregoing forces as a user repeatedly draws the bow's cord 26. The other limb 19 also experiences similar problems.

FIGS. 3 and 4 depict an archery bow 50 in accordance with an exemplary embodiment of the present disclosure. The bow 50 has two forked limbs 52, 53 similar to the limbs 19, 21 of FIG. 1. Cams 55, 56 are rotatably mounted on the ends of the forked limbs 52, 53, respectively. At least one cord 59 is secured to the cams 55, 56.

FIG. 5 depicts the limb 52 and cam 55. As shown by FIG. 5, the forked limb 52 has two prongs 62, 63 separated by a gap 64 similar to the manner that prongs 22, 23, of FIG. 2 are separated by gap 24. An axle 65 passes through the gap 64, and the cam 55 is rotatably mounted on the axle 65. If desired, nuts (not shown) may be screwed or otherwise positioned on each end of the axle 65 to help secure the axle to the limb 52. Except for the addition of inserts 70, 71, which will be described in more detail hereafter, the configuration of limb 52 and cam 55 may be identical to that of limb 21 and cam 33, respectively.

As shown by FIGS. 5 and 6, inserts 70, 71 are inserted into prongs 62, 63, respectively. If desired, an adhesive, such as an epoxy, may be used to adhere the inserts 70, 71 to the prongs 62, 63. FIGS. 6-9 depict various perspectives of the limb 52 with the cam 55 removed for illustrative purposes. Further, FIG. 10 shows an end view of the insert 70 for one exemplary embodiment of the present disclosure, and FIG. 11 shows a side view of the insert 70. Further, in the exemplary embodiment described herein, the configuration of insert 71 is identical to that of insert 70, which will be described in more detail herein. For purposes of brevity, the configuration of insert 71 will not be described in as much detail. In other embodiments, it is possible for the inserts 70, 71 to have different configurations.

In the exemplary embodiment shown by FIGS. 3-11, the insert 70 is generally T-shaped, although other shapes are possible. The exemplary insert 70 has a shaft 74 (FIG. 10) that is inserted into prong 62 and a head 75 that extends along a surface 88 of the prong 62. The head 75 may be flat, or it may be rounded, as illustrated in FIG. 10. In the embodiment shown by FIGS. 3-9, the entire head 75 is external to the prong 62, unlike the shaft 74, but at least portions of the head 75 may be within a periphery of the prong 62 in other embodiments. Further, the shaft 74 has a generally rectangular shape, but other shapes are possible in other embodiments.

The shaft 74 preferably has hole 81 (FIG. 11) that allows the axle 65 to pass therethrough. The hole 81 is preferably dimensioned such that the axle 65 just fits through the hole 81. In one embodiment, the insert 70 is composed of a high strength material, such as aluminum, steel, or brass. Moreover, the mechanical properties of the material of the insert 70 are preferably such that the existence of the shaft 74 in the prong 62 provides mechanical support for the prong 62 and enhances the mechanical integrity of the prong 62 regardless of whether the head 75 is present.

The existence of the head 75, however, further enhances the mechanical integrity of the prong 62 by redistributing load exerted by the axle 65 across the prong surface 88 in contact with the head 75. In this regard, a component of the force exerted by the axle 65 tends to pull the insert 70 in the y-direction. Such a force presses the head 75 against the surface 88 of the prong 62. Thus, the head 75 helps to distribute the force across greater surface area relative to the forces exerted by axle 25 of FIG. 2 helping to reduce pressure at various points that would otherwise be under greater pressure. In addition, the head 75 redistributes forces further from the leading edge of the prong 62 enhancing the ability of the prong 62 to withstand forces exerted by the axle 65 when the cord 59 is drawn.

To better illustrate the foregoing, refer to FIG. 12, which depicts the prong 22 of the conventional limb 21 depicted by FIG. 1. As shown by FIG. 12, the prong 22 has a hole 71 through which the axle 25 (FIG. 2) passes, and the axle 25 is not shown in FIG. 12 for illustrative purposes. The y-component of a force exerted by the axle 25 is distributed from approximately point A to point B along a surface 101 that contacts the axle 25. The forces exerted by the axle 25 tend to push the prong 22 at least in the y-direction, and edge 103 is referred to as the “leading edge.” In general, for forces in the y-direction, the further that a force is applied from the leading edge 103, the better that the prong 22 can withstand the force without failing as there is more material between the point of the force and the leading edge 103. Moreover, the forces in the y-direction exerted by axle 25 on surface 101 are applied at distances ranging between approximately y₁ and Y₂ from the leading edge 101.

FIG. 13 depicts the prong 62 of limb 52 (FIG. 4). As shown by FIG. 13, the prong 62 has a hole 72 through which the axle 65 (FIG. 6) passes, and the axle 65 and the insert 70 are not shown in FIG. 13 for illustrative purposes. Referring to FIGS. 10 and 13, the insert 70 redistributes at least some force across the prong surface 88 contacting the head 75 such that some of the force exerted by the axle 65 is applied from point C to point D, which are a distance y₃ from the leading edge 112 of prong 62. Thus, if the prongs 22, 62 are of equal width (in the y-direction), then the forces applied by head 75 on the surface 88 are further from the leading edge 112 as compared to the forces applied by axle 25 on the surface 101 relative to leading edge 103. In fact, if the holes 71, 72 are the same size and if the centers of the holes 71, 72 are along the centerlines 78, 79 of the prongs 22, 62, respectively, then the forces applied by the head 75 on the surface 88 are about twice as far from the leading edge 112 as compared to the forces applied by axle 25 on the surface 101 relative to leading edge 103, assuming that the widths of prongs 22, 62 are equal. Moreover, having the insert 70 redistribute forces from the axle 65 across the surface 88 increases the width between the leading edge 112 and the points where these forces are applied thereby enhancing the mechanical integrity of the prong 62 when a user draws the cord 59.

In addition, the insert 71 may be identical to the insert 70 described above except that insert 71 is inserted into the prong 63 instead of prong 62. Thus, like insert 70, the insert 71 may have a shaft and a head. Further, the insert 71 may have a similar effect to the mechanical integrity of prong 63 as does insert 70 to prong 62. Indeed, inserting the inserts 70, 71 into the prongs 62, 63, respectively, enhances the mechanical integrity of the limb 52 such that it is better able to withstand forces induced by a user pulling cord 59. Further, inserts may be similarly inserted into the forked limb 53 to enhance the mechanical integrity of this limb 53.

It should be noted that the inserts 70, 71 may be used on various types of bows, including solid limb bows, split limb bows, cross bows, and other types of known or future-developed bows. Further, FIG. 3 shows a bow 50 that has cams located at the end of each limb. Locating a cam at the end of either limb is unnecessary. Indeed, the exemplary bow 50 shown by FIGS. 3-9 is presented for illustrative purposes, and various modifications to the bow 50 and/or inserts 70, 71 would be apparent to one of ordinary skill in the art upon reading this disclosure.

FIG. 14 depicts an end view of a prong 111 of a bow limb having an insert 120 inserted into the prong 111 in accordance with an exemplary embodiment of the present disclosure. Similar to the insert 70, the insert 120 has a shaft 124 inserted into the prong 111 and a head 125 that extends along and contacts a surface 131 of the prong 111. Further, holes 135 for receiving an axle (not shown) on which a cam (not shown) may be mounted, pass through the prong 111. A similarly-sized hole 136 passes through the shaft 124 and is aligned with the holes 135 in the prong 111.

FIG. 15 depicts a side view of the prong 111, and FIG. 16 depicts a planar view of the prong 111. Preferably, an axle passing through the holes 135, 136 fits snugly through the shaft 124 so that force from the axle is transferred by insert 125 to the prong surface 131. Thus, the insert 125 redistributes force from the axle passing through the holes 135, 136 across the surface 131, as described above for prong 70.

If desired, portions of the insert 125 can be beveled or rounded in an effort to remove sharp edges. For example, FIGS. 17 and 18 show a side view and a planar view, respectively, after the head 125 has been beveled. However, such shaping of the insert 116 is unnecessary.

FIG. 19 shows an end view of the prong 111 of a bow limb having an insert 150 inserted into the prong 111 in accordance with an exemplary embodiment of the present disclosure. The insert 150 is identical to the insert 120 shown in FIGS. 14-16 except that the insert 150 has a tab 163, which has a hole 165. Thus, the insert 150 has a shaft 154, a head 155, and a hole 156 passing through the shaft 154, similar to the insert 120. FIGS. 20 and 21 depict a side view and a planar view, respectively, of the prong 111 and insert 150. As shown by FIG. 22 a weight 171 may be attached to the tab 163. In one exemplary embodiment, the weight 171 comprises an element 173, such as a solid piece of brass or other material, and a cord 175 that is used to tie or otherwise attach the element 173 to the tab 163. For example, the cord 175 may pass through the hole 165 and be tied to the tab 163.

The weight of the element 173 provides the arrow or other projectile being launched by the bow with more momentum. In one exemplary embodiment, the weight of the element 173 is about one-quarter of a pound, but the element 173 may have other weights in other embodiments. Further, the shape of the element 173 is immaterial, and the element 173 may have any of a variety of shapes. Further, the element 173 can be attached to the insert 150 via various techniques and configurations.

Each of the components 154, 155, and 163 of insert 150 are integral with respect to each other. In at least one embodiment, the insert 150 is a unitary piece of metal or other material. For example, the insert 150 may be formed by an extrusion or other process that simultaneously forms each of the components 154, 155, 163 by shaping a single piece of metal or other material. In other examples, other techniques could be employed. For example, the tab 163 and/or shaft 154 may be welded to the head 155.

It should be noted that various techniques may be used to manufacture a bow having an insert positioned within a bow limb, as described herein. Exemplary manufacturing techniques will be described in detail below, but it should be emphasized that other manufacturing techniques are possible as well.

During manufacture of a bow, a prong 211 of a bow limb is cut to form a channel 214, as depicted by FIGS. 23 and 24 and by block 218 of FIG. 25. As shown by FIG. 24, the channel 214 extends from one prong surface 215 to another surface 216 that is opposite of the surface 215. A shaft 227 of an insert 225, such as is depicted in FIGS. 26 and 27, is then inserted into the channel 214 such that a head 228 of the insert 225 contacts the surface 215 of the prong 211, as depicted by FIGS. 28 and 29 and block 230 of FIG. 25. In the exemplary embodiment shown by FIGS. 26-29, the insert 225 has a tab 236 formed on the head 228, but such a tab 236 is unnecessary. Before the insert 225 is moved into the channel 214, epoxy or some other adhesive material is applied to the surfaces of the insert 225 that are to contact the prong 211. Thus, once the insert 225 is positioned in the prong 211 and the epoxy or other adhesive material cures, the insert 225 adheres to the prong 211. In one exemplary embodiment, the length of the channel 214 in the z-direction (FIG. 28) is about equal to the length of the shaft 227 in the z-direction such that the shaft 227 fits snuggly in the prong 211 and opposite sides of the shaft 227 contact the channel walls defining the channel 214.

In the exemplary embodiment shown by FIGS. 28 and 29, the width of the shaft 227 in the y-direction is greater than the width of the prong 211 such that the shaft 227 extends below the prong 211. As depicted by block 252 of FIG. 25, the insert 225 is then sanded or otherwise shaped as desired. For example, the shaft 227 may be sanded such that it is flush with the prong 211, as depicted by FIG. 30. Further, the head 228 may be beveled and/or rounded via a sanding process. As shown by block 255 of FIG. 25, holes for receiving an axle may be drilled through the prong 211 and the insert 225.

Note that similar techniques may be employed to retrofit an existing bow with one or more inserts in accordance with the present disclosure. In this regard, the axle on which a cam is mounted may be removed from a bow limb. Then, the process depicted by FIG. 25 and described above may be used to add at least one insert. However, there are already holes for receiving an axle in the prong, and there is no reason to perform block 255.

Positioning an insert into an end of a bow limb, as described herein, generally increases the mechanically integrity of the bow limb. In particular, the presence of the insert increases the amount of force that the bow limb can withstand and helps to extend the useful life of the bow. Further, in the event that the bow limb does fracture or otherwise fail, the presence of the insert can help reduce the extent to which the limb is damaged thereby helping to prevent or reduce bodily injury. 

1. An archery bow, comprising at least one forked limb having a first prong and a second prong separated by a gap; an axle passing through the first and second prongs; and a first insert having a shaft and a head, the shaft positioned in the first prong, the axle passing through the shaft, and the head extending along a first surface of the first prong.
 2. The bow of claim 1, further comprising a second insert having a shaft and a head, the shaft of the second insert positioned in the second prong, the axle passing through the shaft of the second insert, and the head of the second insert extending along a surface of the second prong.
 3. The bow of claim 1, wherein the insert has a tab extending from the head, the tab having a hole.
 4. The bow of claim 1, wherein the head is external to the first prong.
 5. The bow of claim 1, further comprising a cam rotatably mounted on the axle.
 6. The bow of claim 5, further comprising a cord attached to the cam and to at least one other point on the bow.
 7. The bow of claim 1, wherein the first prong has a channel extending from the first surface to a second surface of the first prong, the second surface opposite of the first surface, and wherein the shaft is positioned in the channel.
 8. The bow of claim 7, wherein the head contacts the first surface.
 9. The bow of claim 7, wherein the shaft and the channel are dimensioned such that the shaft fits snugly in the first prong.
 10. An archery bow, comprising: at least one forked limb having a first prong and a second prong separated by a gap, the first prong having a first surface; an axle passing through the first and second prongs; a cam rotatably mounted on the axle; a cord attached to the cam and to at least one other point on the bow; and means for transferring a force from the axle to the first surface of the first prong, the force generated by a user pulling on the cord, a portion of the transferring means inserted into the first prong, the portion having a hole through which the axle passes.
 11. The bow of claim 10, wherein the first prong has a second surface that is opposite of the first surface, wherein the first prong has a channel extending from the first surface to the second surface, and wherein the portion is positioned in the channel.
 12. A forked bow limb having a first prong and a second prong separated by a gap, wherein an insert is positioned in the first prong, the insert having a shaft and a head, the head extending along a surface of the first prong and the shaft positioned in a channel of the first prong, wherein an axle passes through the first prong, the second prong, and the shaft.
 13. The forked bow limb of claim 12, wherein a cam is mounted on the axle.
 14. A method, comprising the steps of: providing a bow, the bow having a forked bow limb and a cam that is rotatably mounted on an axle passing through a first prong and a second prong of the forked bow limb, the cam secured to a cord; pulling the cord thereby generating a force passing through the axle; and transferring the force from the axle to a surface of the first prong via an insert that is positioned in the first prong, the insert having a hole through which the axle passes, the insert further having a head that is external to the first prong and that extends along the surface. 